Turbochargers include a turbine and a compressor that may be connected by a shaft. The turbine is located in a turbine stage section of the turbocharger. The geometries and components in the turbine stage section are factors that may influence turbocharger efficiency and performance. In particular, geometries and components that affect exhaust flow, such as a turbo casing and diffuser, may allow an undesirable loss of energy from exhaust flow if not properly designed.